Abstract:

Half-cell reactions and alkaline direct ethylene glycol and glycerol fuel cells (DEGFC
and DGFC) have been studied on Pd-based ternary core–shell (FeCo@Fe@Pd)
nanocatalyst using multi-walled carbon nanotubes bearing carboxylic (MWCNT-COOH)
and sulfonic acid (MWCNT-SO3H) as supporting platforms. The core–shell–shell nature
of this nanocatalyst, obtained via the “microwave-induced top-down nanostructuring and
decoration”, was clearly proven from atomic resolution transmission electron microscopy
(ARTEM). The functional groups of the MWCNTs show a huge impact on the physicochemical
properties of the FeCo@Fe@Pd nanocatalyst towards the electrocatalytic
oxidation of EG and GLY in alkaline media. The FeCo@Fe@Pd on –COOH-treated
MWCNTs showed the small particle size of ca. 7.4 nm, uniform loading of the catalyst
on the support, large electrochemically-active surface area and enhanced electrocatalytic
activity compared to the FeCo@Fe@Pd on –SO3H-bearing MWCNTs. As a preliminary
test, FeCo@Fe@Pd/MWCNT-COOH was used for passive, air-breathing anion-exchange
membrane based fuel cells (AEM-DEGFC and AEM-DGFC). The analysis of the exhaust
products, established using NMR spectroscopy, revealed a high selectivity towards the
complete oxidation of both EG and GLY under benign experimental conditions.